Amazon.com Inc. said Tuesday it doesn't expect a quick resolution of a contract dispute with Hachette Book Group that has led to Amazon restricting the sale of some Hachette titles.

The comments were Amazon's first acknowledging the dispute, which has sparked criticism that the company is unfairly wielding its clout as the country's largest online and digital bookseller. The Seattle retailer has halted preordering of many Hachette...